In this grant application we are proposing extensive studies of the metabolism of collagen and its biosynthetic precursor, procollagen, by cultured human skin fibroblasts in control and disease states. The major goal of this research is to exactly define the molecular defects which may occur in the biochemistry of collagen in diseases affecting the connective tissues of skin and other organs. The major emphasis will be on diseases in which previous investigations by us and others have revealed connective tissue abnormalities, but in which the exact nature and the exact extent of collagen aberrations are currently unknown. Such diseases include psoriasis, benign and malignant skin tumors, scleroderma, the Ehlers-Danlos syndrome, and osteogenesis imperfecta. For comparison, parallel studies will be performed employing control fibroblasts from subjects without connective tissue abnormalities. The parameters to be studied include rate of procollagen synthesis by the culture fibroblast, as well as isolation, identification, and characterization of the genetically distinct procollagen. In order to understand changes in collagen metabolism in the fibroblast cultures in diseases, additional studies will be performed on the structure and metabolism of genetically distinct procollagens synthesized by normal human skin fibroblasts. Specifically, the procollagens will be isolated in quantitative amounts in order to allow further chemical characterization. The purification of the procollagens will also enable us to develop radioimmunoassays, based on type-specific antibodies, which will then be utilized in studies of collagen formation in diseases. The antibodies are also employed in investigations concerning the control mechanisms involved in the biosynthesis of procollagen as well as in identification of products in a cell-free translation system to be developed for assay of procollagen messenger-RNA.